The purpose of this application is to determine nonhazardous power levels in the mechanism of formation of cataract following chronic occupational exposure to near infrared (700-2000 nm) irradiation. The infrared irradiation will be delivered to the iris and lens, both together and separately. After the chronic infrared exposures are made the exposed lenses will be analyzed by a variety of optical and chemical tests to detect any early or precataractous changes. The tests will be designed to detect the presence of any abnormal molecules resulting from the infrared exposures and will include spectral absorption, fluorescence and polarization measurements as well as chemical tests, to determine changes in concentration of any amino acids and types of proteins normally present and the appearance of any unusual molecules. Acute high energy exposures in animals will model possible changes that take place in the formation of cataract from chronic low level infrared irradiation.